A child. Primarily used in the phrase "little pitchers have big ears," meaning children hear everything, especially when you least expect them to. (The "ear" of a water pitcher is the handle.) Please watch what you say around the kids—little pitchers have big ears, you know. A: "Where did Susie learn such an inappropriate word?" B: "Who knows. Little pitchers like her tend to hear all sorts of things."
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.